Apparatuses for moulding plastic preforms into plastic containers have been known from the prior art for a long time. Some conventional blow moulding machines comprise a blow mould, inside which the plastic preforms are expanded through the application of pressure to form plastic containers. During this stretch-blow moulding of plastic containers, so-called oligomers, i.e. short-chain molecules or foreign substances, are excreted onto the blow mould from the plastic of the plastic preforms. The surface of these blow moulds therefore becomes dull and in the extreme case rough as it becomes increasingly soiled. However, this has negative effects on the bottle quality, since this may lead to the situation whereby the bottle appearance may become cloudy on account of the dull blow moulds or else the cooling on the mould surface is reduced as a result of the roughness.
Since both of these problems are unacceptable, the blow moulds must be cleaned and usually polished at regular intervals. Particularly high degrees of soiling by oligomers occur when working with high mould temperatures for process reasons (e.g. in the case of hot fill processes), since soiling is much faster with hot moulds and the cleaning of the moulds in the hot state can be carried out only with a safety risk due to the risk of burning. Particularly in the case of a so-called hot filling installation with a blow moulding machine and a filler block, this cleaning of the moulds is often a very negative aspect. Another aspect for the cleaning of blow moulds, even in the case of so-called cold moulds (e.g. below 100° C.), is hygiene. Particularly when bottling sensitive products, it is important to avoid as far as possible any spreading of germs or spores on the outer wall of the bottle in the filler region. Regular and good cleaning of the blow moulds helps to ensure this. Cleaning is thus always to be understood also to mean a reduction in germs and spores.
A container production apparatus and a production method for moulded bodies are known from WO 2008 125216 A2. In this case, a radiation device is arranged at or on the blow moulding machine, the radiation being directed at least onto one region of the blow moulding machine.
It may therefore be desirable to simplify the cleaning of such blow moulding machines and to provide an automated method for cleaning blow moulds.